I do that and my score has remained in the neighborhood of 830. Haven't had any mortgages or other loans either for at least 7 years.
There’s secured credit, ie. mortgage and car loans, both of which have leins attached and which can be taken from you if you default.
And then there’s unsecured credit - what you can sign for. Which is what I’m talking about. An any-time, for any reason, any-where, on-demand, on-your-signature limit you earn and that is increased based on a solid repayment history. Each increase is a reflection in how trustworthy you are voluntarily paying on time, as opposed to the constraints of a coercive loan like a mortgage, where mandatory payments are enforced by withholding title.
So when the car blows a head gasket, or Johnny takes it in the teeth at the little league game five weeks before Christmas, instead of draining the bank account while you’re waiting for the insurance check, begging the boss for a payroll advance, or adding another credit-dinging home equity loan for the ortho bill, you have signature credit lines that allow you to spread the expense over 3 or 6 months, adding to your credit rating and increasing your perks at the same time.